PP bottle injection, drawing and blowing integrated forming equipment and processing method thereof

Abstract

The invention relates to the field of blow molding, in particular to PP bottle injection-stretch-blow integrated molding equipment and a processing method thereof.The PP bottle injection-stretch-blow integrated molding equipment comprises an extruder and a case and is characterized in that a rail is mounted in the case, a stretching mechanism is slidably connected to the outer side of the rail, a parison mold and a blow molding mold assembly are further mounted in the case, and the upper end of the rail is arc-shaped; the lower end of the blow molding mold assembly is linear and perpendicular to the ground, the blow molding mold assembly is of a rotatable structure, a parison is adopted for discharging in the direction parallel to the ground and is put into a blow molding mold, the parison belongs to an intermediate product, transverse stretching and blow molding are conducted on the basis of the parison, and the parison is in an unsolidified state under the action of natural gravity; the raw materials on the surface of the parison can slightly flow downwards in the direction of the figure 6, due to the fact that the product with the handle is asymmetrical in the left-right direction, the handle needs more materials, and the flow just fills more materials needed by the handle.

Description

Technical Field

[0001] The present invention relates to the field of blow molding, and particularly to an integrated injection stretch blow molding device for PP bottles and its processing method. Background Art

[0002] Blow molding is one of the common ways to produce plastic products, and the main products produced are bottle bodies. The parison is blown into the shape of the plastic bottle itself in the mold. Since the blow molding process is fast, it is suitable for large-scale production.

[0003] In the blow molding process, there have always been design process defects in asymmetric plastic bottles with handles. In the existing stretch blow molding process, the parison needs to be stretched to the maximum length first and then blown. Since the handle is not in the main stretching path and the blowing process is uniform, when the plastic expands towards the handle, it will enter the handle from both the upper and lower ends of the handle at the same time and finally converge in the middle of the handle. And the handle is a frequently used position of the product. When the weight of the stored liquid is large and the handle joint is located in the center, it is very easy to break because the handle here is not integrally formed but has a plastic overlapping process in two directions. Therefore, it is necessary to redesign the processing method to solve the problem of the handle strength. For this reason, technical personnel in this field have designed an integrated injection stretch blow molding device for PP bottles and its processing method to solve the above problems. Summary of the Invention

[0004] Aiming at the above existing technical deficiencies, the purpose of the present invention is to provide an integrated injection stretch blow molding device for PP bottles and its processing method, which can be adapted to the welding of mesh sheets with different spacings.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: It includes an extruder and a chassis. It is characterized in that a track is installed inside the chassis, a stretching mechanism is slidably connected to the outside of the track, a parison mold and a blow molding mold assembly are also installed inside the chassis. The upper end of the track is arc-shaped, and the lower end is straight and perpendicular to the ground. The blow molding mold assembly is a rotatable structure. The center of the arc of the track and the rotation center of the blow molding mold assembly are on the same axis. The discharging direction of the parison mold is parallel to the ground. When the stretching mechanism is not inserted, the discharging direction of the blow molding mold assembly is parallel to the ground. Only after the stretching mechanism is inserted into the blow molding mold assembly and rotated at the same time can demolding be carried out.

[0006] Preferably, the blow molding mold assembly includes a mold body, a semi-circular support frame and an arc-shaped base. The semi-circular support frames are distributed on both sides of the mold body, and the center of the semi-circular support frame is connected to the mold body. The semi-circular support frame and the arc-shaped base form a sliding connection. One side of the arc-shaped base is provided with a bracket that is rotationally connected to the semi-circular support frame through a damping bearing. The center of the semi-circular support frame, the center of the arc-shaped base and the center of the arc of the track are on the same axis.

[0007] Preferably, an exhaust port one, an exhaust port two, an exhaust port three, a control valve and an exhaust port four are arranged inside the mold body, and control valves are installed at the positions where the exhaust port one and the exhaust port two lead to the outside of the mold body.

[0008] Preferably, an inner cavity handle and an inner cavity container are also provided inside the mold body. Before blow molding, the inner cavity handle is parallel to the ground, and the inner cavity handle is closer to the ground than the inner cavity container.

[0009] Preferably, the exhaust port one and the exhaust port two are opened on both sides of the bottom of the inner cavity handle, the exhaust port three is opened in the middle of the inner cavity handle, and the exhaust port four is opened at the bottom of the inner cavity container.

[0010] Preferably, the stretching mechanism includes a substrate, two groups of pulleys and a gear. A rack meshing with the gear of the stretching mechanism is installed on one side of the track. The two groups of pulleys are rotatably connected to one side of the substrate, and the two groups of pulleys are located on the upper and lower sides of the track and form a sliding connection.

[0011] Preferably, the maximum rotatable angle between the stretching mechanism and the blow molding die assembly is 100°.

[0012] Preferably, the stretching mechanism further includes a hydraulic cylinder and a stretching rod connected to the top of the hydraulic cylinder. An air port communicating with the air pump is opened on the surface of the stretching rod.

[0013] Preferably, after the stretching mechanism horizontally inserts into the preform die to obtain a preform and then cooperates with the blow molding die, when the stretching rod of the stretching mechanism carries the preform and moves upward along the straight section of the track, the stretching rod always remains parallel to the ground.

[0014] An integrated injection stretch blow molding device for PP bottles and its processing method include the following steps: Step 1: Start the drive motor on the stretching mechanism to drive the gear meshing with the rack on the track to rotate, so that the stretching mechanism moves straight upward along the track and reaches the specified coordinate point to align with the preform die. Step 2: Start the hydraulic cylinder, push the stretching rod into the preform die, and synchronously close the preform die. The extruder 1 extrudes the molten polypropylene into the preform die, and gradually forms a preform attached to the stretching rod. Step 3: The hydraulic cylinder drives the stretching rod to withdraw from the preform die, and the stretching mechanism continues to rise to the end of the straight section of the track and aligns with the blow molding die assembly. Step 4: The hydraulic cylinder drives the stretching rod to enter the blow molding die assembly, the mold body closes, and then start the hydraulic cylinder again to drive the stretching rod to continue to extend into the mold body. Before reaching the limit position, synchronously start the air pump and the drive motor of the stretching mechanism, and perform blow molding while rotating. Step 5: After blow molding, delay the opening of the control valve. After opening, make the first exhaust port and the second exhaust port exhaust outward. The delay time for opening is 0.2 s to 5 s.

[0015] Step 6: After blow molding is completed, take out the finished product. The beneficial effects of the present invention are as follows: The parison is discharged in a direction parallel to the ground and put into the blow molding mold. The parison is an intermediate product. Transverse stretching and blow molding are carried out on the basis of the parison. Under the action of natural gravity, the parison is in an unfrozen state. The raw materials on the surface of the parison will flow slightly downward along Figure 6 the direction. Since the product with a handle is not symmetrical on the left and right, more materials are required at the handle position. This flow just fills the more materials required at the handle. And during the processes of blow molding and stretching, rotation is carried out synchronously, so that the blown and bulged plastic enters the inner cavity of the handle from the handle position near the bottle mouth. The position below the handle will flow reversely and enter below the handle only after the bottom of the mold is completely filled. At this time, the plastic fluid entering from above the handle almost fills most of the positions of the handle. As Figure 8 shown, compared with the traditional process of stretching first and then blow molding, the handle of the present invention is more integral, has higher strength, and is less likely to break. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 is the front view structural schematic diagram of the present invention.

[0018] Figure 2 is the schematic diagram of the stretching mechanism of the present invention ready to insert into the parison mold.

[0019] Figure 3 is the schematic diagram of the stretching mechanism of the present invention moving upward and inserting into the blow molding mold assembly after taking out the parison.

[0020] Figure 4 is the schematic diagram of the simultaneous upward rotation structure of the stretching mechanism and the blow molding mold assembly of the present invention.

[0021] Figure 5 is the schematic diagram of the mold body structure of the present invention.

[0022] Figure 6 is the schematic diagram of the intermediate product parison of the present invention.

[0023] Figure 7It is a schematic diagram of the unfolding direction of the preform of the present invention after stretching and blow molding.

[0024] Figure 8 It is a schematic diagram of the preform in the mold of the present invention after improvement and unfolding.

[0025] Figure 9 It is a schematic diagram of the preform in the mold of the present invention before improvement and unfolding.

[0026] Figure 10 It is a schematic diagram of the actual product of the present invention before improvement.

[0027] Figure 11 It is a schematic diagram of the actual product of the present invention after improvement.

[0028] In the figure: 1. Extruder; 2. Preform mold; 3. Stretching mechanism; 4. Track; 5. Blow molding die assembly; 501. Die body; 5011. First exhaust port; 5012. Second exhaust port; 5013. Third exhaust port; 5014. Control valve; 5015. Fourth exhaust port; 5016. Inner cavity handle; 5017. Inner cavity container; 502. Semi-circular support frame; 503. Arc-shaped base; 6. Chassis. Specific embodiments

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments.

[0030] Among them, the accompanying drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as a limitation of this patent; in order to better illustrate the embodiments of the present invention, some components in the accompanying drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted.

[0031] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so the terms describing the positional relationship in the accompanying drawings are only for illustrative purposes and should not be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] In the description of the present invention, unless otherwise clearly specified and defined, if terms such as "connection" are used to indicate the connection relationship between components, such terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0033] Embodiment 1: The present invention provides an integrated injection stretch blow molding device for PP bottles and its processing method. As Figure 1-11 shown, it includes an extruder 1 and a chassis 6. It is characterized in that a track 4 is installed inside the chassis 6, and a stretching mechanism 3 is slidably connected to the outside of the track 4. A preform mold 2 and a blow molding die assembly 5 are also installed inside the chassis 6. The upper end of the track 4 is arc-shaped, and the lower end is linear and perpendicular to the ground. The blow molding die assembly 5 is a rotatable structure. The center of the arc of the track 4 and the rotation center of the blow molding die assembly 5 are on the same axis. The discharging direction of the preform mold 2 is parallel to the ground. When the stretching mechanism 3 is not inserted, the discharging direction of the blow molding die assembly 5 is parallel to the ground. Demolding can only be carried out after the stretching mechanism 3 is inserted into the blow molding die assembly 5 and rotated simultaneously. The blow molding die assembly 5 includes a die body 501, a semi-circular support frame 502, and an arc-shaped base 503. The semi-circular support frames 502 are distributed on both sides of the die body 501. The semi-circular support frames 502 play a supporting role for the die body 501. Slide bars are provided on the left and right sides of the die body 501. A hydraulic telescopic rod is installed at the top of one of the semi-circular support frames 502. The die body 501 can move back and forth on the slide bars under the push or pull of the hydraulic telescopic rod. Only the upper die of the die body 501 needs to be controlled. The center of the semi-circular support frame 502 is connected to the die body 501. The semi-circular support frame 502 and the arc-shaped base 503 form a sliding connection. A bracket that is rotationally connected to the semi-circular support frame 502 through a damping bearing is provided on one side of the arc-shaped base 503. The center of the semi-circular support frame 502, the center of the arc-shaped base 503, and the center of the arc of the track 4 are on the same axis. The combination of the semi-circular support frame 502 and the arc-shaped base 503 realizes the stability of the die body 501 during rotation, and the semi-circular support frame 502 never disengages from the inside of the arc-shaped base 503. During rotation, both the die body 501 and the semi-circular support frame 502 rotate around the center of the arc section of the track 4.

[0034] Inside the mold body 501, there are an exhaust port 1 5011, an exhaust port 2 5012, an exhaust port 3 5013, a control valve 5014, and an exhaust port 4 5015. Control valves 5014 are installed at the locations where the exhaust port 1 5011 and the exhaust port 2 5012 lead to the outside of the mold body 501. The control valve 5014 is delayed in opening after the blow molding starts. After opening, it releases the trapped air inside the mold body 501 to the outside. The reason for the delayed opening is: to prevent the plastic expansion body from immediately adhering to the inner wall, so that trapped air is formed at F1 and F2 as shown in Figure 8 to restrict the diameter size of the plastic below. After contacting the plastic expansion body above, the plastic expansion body below is wrapped into the interior by the plastic expansion body above, making the seam mark located inside the plastic expansion body above.

[0035] Inside the mold body 501, there are also an inner cavity handle 5016 and an inner cavity container 5017. The inner cavity handle 5016 can form part of the plastic part handle, and the inner cavity container 5017 is responsible for forming part of the main bottle body of the plastic part. After the plastic bottle body is formed, the handle and the inside of the main bottle body are interconnected. Before blow molding, the inner cavity handle 5015 is parallel to the ground, and the inner cavity handle 5016 is closer to the ground than the inner cavity container 5017. The part forming the plastic handle should face downward because the parison is taken out horizontally, and it is also in a state parallel to the ground when moving upward. Before the parison is completely cooled, it still has a certain fluidity and will flow vertically downward slightly along the Figure 6 direction of C1 in to form a situation where there is more raw material on one side of the parison and less on the other side. In conventional production, it is normal for the parison to sag, and the sag here can be used to fill the handle with more material, avoiding the situation of material shortage at the handle after the product is formed.

[0036] The exhaust port 1 5011 and the exhaust port 2 5012 are opened on both sides of the bottom of the inner cavity handle 5015. The exhaust port 1 5011 and the exhaust port 2 5012 improve the exhaust efficiency at the root of the handle from both sides. The exhaust port 3 5013 is opened in the middle of the inner cavity handle 5016, and the exhaust port 4 505 is opened at the bottom of the inner cavity container 5017. Both the exhaust port 3 5013 and the exhaust port 4 505 are for normal exhaust, and the gas is automatically discharged outward when the plastic body expands and squeezes the gas. Embodiment 2 is different from Embodiment 1 in that: the stretching mechanism 3 includes a substrate, two groups of pulleys, and a gear. A rack meshing with the gear of the stretching mechanism 3 is installed on one side of the track 4. A driving motor is installed at the stretching mechanism 3 to drive the gear. The gear rotates and meshes with the rack for transmission, driving the entire stretching mechanism 3 to climb upward. The two groups of pulleys are rotatably connected to one side of the substrate. The two groups of pulleys are located on the upper and lower sides of the track 4 and form a sliding connection, and the two groups of pulleys play a role in clamping the stretching mechanism 3 on the track 4 and achieving smooth movement.

[0037] The maximum rotatable angle between the stretching mechanism 3 and the blow molding die assembly 5 is 100°. The stretching mechanism 3 and the blow molding die assembly 5 need to rotate from 0° to more than 90°. Since the preform is formed horizontally and transported horizontally, due to the natural gravity, the raw materials on the preform will still flow because the temperature is still high. Utilizing the flowing characteristics, when the preform is placed into the blow molding die assembly 5, more materials are often required at the handle. And due to the downward fall of natural gravity, more raw materials flow downward. As Figure 6 shown, place it horizontally and start blow molding. Rotate during the blow molding process to guide the raw material fluid to enter first from the direction near the bottle mouth of the inner cavity handle 5016. After rotation, guide the raw material fluid to fall rapidly and keep the blow molding uniform in other places. When the lower part of the inner cavity container 5017 has been filled, it flows back to the upper part and enters from the bottom of the inner cavity handle 5016. At this time, the plastic fluid that entered from above first has filled the inner cavity handle 5016 completely. The two contact each other at the root of the handle, realizing the integrity of the plastic bottle handle and avoiding the occurrence of fracture. As Figure 8 and Figure 11 shown at, Figure 10 In [Figure Figure 10 ], point G1 is the seam point of the product before improvement, and it is prone to fracture when lifted. Figure 11 In [Figure Figure 11 ], point H1 is the seam point of the product after improvement. The lifting point and the hand are not in the same position, and it is not easy to fracture.

[0038] The stretching mechanism 3 further includes a hydraulic cylinder and a stretching rod connected to the top of the hydraulic cylinder. The stretching rod is provided with air ports communicating with an air pump on its surface. The stretching rod is responsible for the bearing after the preform is formed and pushing the preform downward to stretch within the mold body 501. Gas can be blown inward at the opening to promote the preform to expand to the edge of the mold body 501 to form a complete plastic bottle.

[0039] After the stretching mechanism 3 horizontally inserts into the preform mold 2 to obtain the preform, it then cooperates with the blow molding die 5. When the stretching rod of the stretching mechanism 3 carries the preform and moves upward along the straight section of the track 4, the stretching rod always remains parallel to the ground. The stretching rod needs to maintain a horizontal state before rotation, so that the preform that has not completely solidified will actively flow to one side under the action of gravity, realizing a state where there is more raw material on one side than the other. More raw materials can be obtained at the handle during blow molding, effectively avoiding the occurrence of plastic deficiency after molding.

[0040] An integrated injection stretch blow molding device for PP bottles and its processing method include the following steps: Step 1: Start the drive motor on the stretching mechanism 3 to drive the gear meshing with the rack on the track 4 to rotate, so that the stretching mechanism 3 moves straight upward along the track 4 and reaches the specified coordinate point to align with the preform mold 2; Step 2: Start the hydraulic cylinder, push the stretching rod into the preform mold 2, and synchronously close the preform mold 2. The extruder 1 extrudes the molten polypropylene into the preform mold 2, gradually forming a preform attached to the stretching rod. Step 3: The hydraulic cylinder drives the stretching rod to withdraw from the preform mold 2, and the stretching mechanism 3 continues to rise to the end of the straight section of the track 4 and aligns with the blow molding die assembly 5. Step 4: The hydraulic cylinder drives the stretching rod into the blow molding die assembly 5, the mold body 501 closes, and the hydraulic cylinder is started again to drive the stretching rod to continue extending into the mold body 501. Before reaching the limit position, the air pump and the drive motor of the stretching mechanism 3 are synchronously started, and blowing and rotation are carried out simultaneously. Step 5: After starting the blowing, delay the opening of the control valve 5014. After opening, make the first exhaust port 5011 and the second exhaust port 5012 exhaust outward. The delay time for opening is 0.2 s to 5 s. Step 6: After the blow molding is completed, take out the finished product. During use, start the stretching mechanism 3 to move it upward along the direction of the track 4 and cooperate with the preform mold 2. The molten polypropylene is extruded into the preform mold 2 through the extruder 1 to form a preform, which is then brought into the upper blow molding die assembly 5 by the stretching mechanism 3. After entering the blow molding die assembly 5, stretching is first carried out, and blowing is carried out during the stretching process, and the blow molding die assembly 5 and the stretching mechanism 3 are rotated together. The rotation angle should be greater than 90°. Finally, open the blow molding die assembly 5 to take out the finished product. It should be noted that the above specific embodiments are only the preferred embodiments of the present invention and the applied technical principles. Those skilled in the art should understand that various modifications, equivalent replacements, changes, etc. can be made to the present invention. However, as long as these transformations do not deviate from the spirit of the present invention, they should be within the protection scope of the present invention. In addition, some terms used in the description and claims of this application are not restrictive, but are only for the convenience of description.

Claims

1. An integrated injection stretch blow molding device for PP bottles, comprising an extruder (1) and a chassis (6), characterized in that, Inside the chassis (6), a track (4) is installed. A stretching mechanism (3) is slidably connected to the outside of the track (4). A preform mold (2) and a blow molding die assembly (5) are also installed inside the chassis (6). The upper end of the track (4) is arc-shaped, and the lower end is straight and perpendicular to the ground. The blow molding die assembly (5) is a rotatable structure. The center of the arc of the track (4) and the rotation center of the blow molding die assembly (5) are on the same axis. The discharging direction of the preform mold (2) is parallel to the ground. When the stretching mechanism (3) is not inserted, the discharging direction of the blow molding die assembly (5) is parallel to the ground. Only after the stretching mechanism (3) is inserted into the blow molding die assembly (5) and rotated simultaneously can demolding be carried out.

2. The integrated injection stretch blow molding equipment for PP bottles according to claim 1, wherein The blow molding die assembly (5) includes a die body (501), a semi-circular support frame (502), and an arc-shaped base (503). The semi-circular support frames (502) are distributed on both sides of the die body (501), and the center of the semi-circular support frame (502) is connected to the die body (501). The semi-circular support frame (502) and the arc-shaped base (503) form a sliding connection. On one side of the arc-shaped base (503), there is a bracket that is rotatably connected to the semi-circular support frame (502) through a damping bearing. The center of the semi-circular support frame (502), the center of the arc-shaped base (503), and the center of the arc of the track (4) are on the same axis.

3. The PP bottle injection stretch blow molding integrated forming equipment according to claim 2, characterized in that, Inside the die body (501), there are an exhaust port one (5011), an exhaust port two (5012), an exhaust port three (5013), a control valve (5014), and an exhaust port four (5015). Control valves (5014) are installed at the places where the exhaust port one (5011) and the exhaust port two (5012) lead to the outside of the die body (501).

4. The integrated injection stretch blow molding equipment for PP bottles according to claim 2, characterized in that, Inside the die body (501), there are also an inner cavity handle (5016) and an inner cavity container (5017). Before blow molding, the inner cavity handle (5015) is parallel to the ground, and the inner cavity handle (5016) is closer to the ground than the inner cavity container (5017).

5. The PP bottle injection stretch blow molding integrated forming equipment according to claim 4, characterized in that, The exhaust port one (5011) and the exhaust port two (5012) are opened on both sides of the bottom of the inner cavity handle (5015). The exhaust port three (5013) is opened in the middle of the inner cavity handle (5016). The exhaust port four (505) is opened at the bottom of the inner cavity container (5017).

6. The integrated injection stretch blow molding equipment for PP bottles according to claim 1, characterized in that, The stretching mechanism (3) includes a substrate, two groups of pulleys, and a gear. A rack that meshes with the gear of the stretching mechanism (3) is installed on one side of the track (4). The two groups of pulleys are rotatably connected to one side of the substrate. The two groups of pulleys are located on the upper and lower sides of the track (4) and form a sliding connection.

7. The integrated injection stretch blow molding equipment for PP bottles according to claim 1, characterized in that, The maximum rotatable angle between the stretching mechanism (3) and the blow molding die assembly (5) is 100°.

8. The integrated injection stretch blow molding equipment for PP bottles according to claim 1, characterized in that, The stretching mechanism (3) also includes a hydraulic cylinder and a stretching rod connected to the top of the hydraulic cylinder. An air port that communicates with an air pump is opened on the surface of the stretching rod.

9. The PP bottle injection stretch blow molding integrated forming equipment according to claim 8, characterized in that, The stretching mechanism (3) horizontally inserts into the preform mold (2) to obtain a preform and then cooperates with the blow molding die (5). When the stretching rod of the stretching mechanism (3) carries the preform and moves upward along the straight section of the track (4), the stretching rod always remains parallel to the ground.

10. A PP bottle injection stretch blow molding integrated forming device and its processing method according to claim 3, characterized in that, Including the following steps: Step 1: Start the drive motor on the stretching mechanism (3) to drive the rotation of the gear that meshes with the rack on the track (4), and move the stretching mechanism (3) linearly upward along the track (4) to reach the specified coordinate point and align with the preform mold (2). Step 2: Start the hydraulic cylinder to push the stretching rod into the preform mold (2), and simultaneously close the preform mold (2). The extruder (1) extrudes the molten polypropylene into the preform mold (2) to gradually form a preform attached to the stretching rod. Step 3: The hydraulic cylinder drives the stretching rod to withdraw from the preform mold (2), and the stretching mechanism (3) continues to rise to the end of the straight section of the track (4) and aligns with the blow molding die assembly (5). Step 4: The hydraulic cylinder drives the stretching rod to enter the blow molding die assembly (5), the mold body (501) closes, and the hydraulic cylinder is started again to drive the stretching rod to continue extending into the mold body (501). Before reaching the limit position, the air pump and the drive motor of the stretching mechanism (3) are started simultaneously to perform blow molding while rotating. Step 5: Open the control valve (5014) with a delay after starting blow molding. After opening, make the first exhaust port (5011) and the second exhaust port (5012) exhaust outward, and the delay time for opening is 0.2 s to 0.5 s. Step 6: After blow molding is completed, take out the finished product.

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